Mechanism and experimental study on the fruit detachment of Chinese wolfberry through reciprocating vibration

In order to realize the efficient and high-quality mechanical picking for Chinese wolfberry, firstly, the forced reciprocating vibration picking principle of the Chinese wolfberry branch was studied, and the mechanical model of vibration picking was established based on the simplified cantilever model, and the response analysis and solution of all positions for the branch were carried out. At the same time, the critical mechanical model of fruit detachment under the condition of fruit hanging on branches was established, and the theoretical values of inertia force for each component of the branch were obtained. Secondly, through actual measurement and finite element modeling, the natural frequency and forced vibration response simulation for each component of the branch of Chinese wolfberry terminal branch model were both studied, and the relationship between single-point periodic excitation force and high-quality fruit shedding parameters was obtained. Thirdly, according to the conclusion of the picking model, a test bench with many groups of adjustable parameters was built. Finally, the last branch of fruit-hanging Chinese wolf berry for Ningqi No.1 was taken as the experimental object, a four-level orthogonal experiment was designed with three factors: frequency, amplitude and entrance angle. Meanwhile, the net picking rate, damage rate and false picking rate were taken as the evaluating indicators, referring to the comprehensive scores of the three factors. It was concluded that the primary and secondary relations of factors affecting the picking effect are frequency, amplitude and entrance angle, and the best operation parameters are frequency of 20 Hz, amplitude of 15 mm, and entrance angle of 45°, then, a hand-held vibration picker with setting parameters was trial-produced, and the optimal parameter combination was verified in the Chinese wolfberry planting base of the National Chinese wolfberry Engineering and Technology Research Center. The results showed that the net picking rate of ripe Chinese wolfberry was 96.13%, the damage rate of fruit was 1.13%, and the false picking rate was 3.23%, mechanized picking efficiency was 30.28 kg/h, which is 6.65 times that of manual picking. The experimental results are consistent with the simulation results. The research results can provide an important basis for the creation and operation standards of large-scale Chinese wolfberry vibration harvesting equipment.